1899.] NATURAL SCIENCES OF PHILADELPHIA. 125 



A SNOW-INHABITING ENCHYTR.i:iD < Mesenchytraeus solifugus Emery) 



COLLECTED BY MR. HENRY G. BRYANT ON THE MALASPINA 



GLACIER, ALASKA. 



BY J. PEPvCY MOORE. 



The material upon which the present account is based was col- 

 lected by Mr. Henry G. Bryant upon the snow of the Malaspina 

 Glacier, while conducting explorations on Mt. St. Elias during the 

 summer of 1897. The habitat of the worm is so unusual that a 

 somewhat detailed account of its structure and habits seems desir- 

 able. 



The mature examples, of which a considerable number were 

 secured, are slender and linear, having about the form of Fridericia 

 lonrja. They possess on an average 55 somites (43 to 58), and 

 measure 15-20 mm. in length by .6-. 7 mm. in greatest diameter 

 (somite XII). At the oral end is a short, bluntly rounded and 

 somewhat swollen prostomium. The oral somite is slightly en- 

 larged and sharply marked off from the succeeding somite by a 

 <leep furrow. Somites II to V inclusive are somewhat depressed, 

 the remainder of the worm being terete. In contracted specimens 

 these anterior somites are distinctly divided into three annuli each. 

 After increasing gradually to somite XII, the diameter remains 

 quite uniform to about one millimeter from the posterior end, 

 whence it narrows rather abruptly to the truncate anal ring. 



In none of the specimens examined ( about twenty in number) is 

 the cliteUum very distinctly developed, but on the contrary is thin 

 and scarcely extends beyond the limits of the twelfth somite. 



Dorsal pores are entirely absent from the somites, but there is a 

 well-marked cephalic pore near the apex of the prostomium, 

 fig. 7, cp. The external openings of the spermathecse are situ- 

 ated in the centres of a pair of conspicuous elliptical swollen areas 

 (figs. 1 and 2, st.), corresponding to the intersegmental furrow 

 IV-V. These areas are much larger, more glandular, and more 

 conspicuous than is usual in the Enchytrajidse. They lie toward 

 the ventral rather than the dorsal body surface, and the sperma- 



